Lawinenlagebericht

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Kernpunkte

It's spooky out there. You could trigger large avalanches on many slopes. The most dangerous conditions are found where old snow existed before this storm (on many slopes at upper elevations and on shady, NW-N-NE-E middle elevation terrain) and where wind drifts exist. You can trigger large, powerful avalanches remotely—from flatter terrain below, above, and to the sides of steep slopes (click to watch video). 

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    2–3

    Yesterday near Galena Summit, Ethan and his partners saw conditions that were "as bad as [we've] witnessed." They remotely triggered avalanches (see video and photos below), experienced near constant snowpack collapsing, and saw slopes that had cracked like panes of glass during the storm. Monday, Ben remotely triggered an avalanche from 1/4 mile away (video). Yesterday, an oberver reported extensive rumbling collapses in shady terrain near Galena Summit. During the storm, the Sun Valley Ski Patrol was able to ski trigger small avalanches on some steep road cuts and shady slopes while getting terrain ready to open to the public.   

    All slopes that had snow on the ground before the recent storm are extremely suspect. This includes most aspects at upper elevations, and shadier NW-N-NE-E aspects at middle elevations. It will take time (weeks/months?) for the weak, faceted layers and crust+facet combinations to fully adjust to the huge load from this storm. 

    How should we travel? VERY CAREFULLY. Stay off of and out from beneath steep slopes where old snow existed before this storm. Conditions change quickly as you move up in elevation and to shadier aspects; safely traveling in or near middle or upper elevation avalanche terrain today will require a cautious attitude, expertise, and near-constant vigilance to avoid slopes with old, weak snow beneath the storm snow. You can significantly reduce the chances of getting caught in an avalanche by sticking to terrain free from wind-effects where the storm snow fell on dirt or bare ground.  

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2–2.5

    Expect to find 2-5 foot thick drifts and slabs in exposed terrain. The wind slabs will be most hazardous where they overlie weak layers (see Problem 1) or slick, icy crusts on more south-facing slopes. However, variations in wind speeds and direction during the storm probably formed slabs that could fail on layers within the storm snow as well. The wind slabs will be thickest, widest, and most widespread at upper elevations, but you may encounter them in middle elevation terrain too. 

    Given the 3-5 feet of new snow and strong winds in recent days, the wind slabs are not an easily manageable problem. Also, the changing wind direction last night may have hidden some large, recently-formed wind slabs. 

    How should we travel? The easy answer is to avoid wind-loaded avalanche terrain. Now is not the time to try to thread the proverbial needle while you're traveling in the mountains. If you see cracks shooting out from your boards or sled, it's time to pay close attention while you head to more sheltered terrain.  

Avalanche Discussion

Whether we're talking about materials, systems, or living things, one statement generally holds true: rapid changes create stress and can cause failure. Our feeble, early season snowpack just increased in depth by a minumum of 3-10 times in the past few days. It will probably take weeks for the snowpack to adjust to the huge load from this storm. Fortunately, there's a ton of amazing skiing and riding to be found in areas where the storm snow fell on bare ground and the wind did not blow. I love it when the best riding and sliding conditions are the same places we're less likely to trigger avalanches. Pay attention to the terrain above you as remote triggered avalanches are a very real possibility.  

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